CN1113334C - Magnetic tunnel junction magnetoresistive read head with longitudinal and transverse bias - Google Patents

Magnetic tunnel junction magnetoresistive read head with longitudinal and transverse bias Download PDF

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CN1113334C
CN1113334C CN99106498A CN99106498A CN1113334C CN 1113334 C CN1113334 C CN 1113334C CN 99106498 A CN99106498 A CN 99106498A CN 99106498 A CN99106498 A CN 99106498A CN 1113334 C CN1113334 C CN 1113334C
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layer
sensing
ferromagnetic layer
magnetic
ferromagnetic
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CN1237755A (en
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小R·E·丰塔纳
S·S·P·帕金
曾庆骅
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Maxell Digital Products China Co Ltd
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International Business Machines Corp
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B2005/3996—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices

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  • Crystallography & Structural Chemistry (AREA)
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  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Magnetic Heads (AREA)
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Abstract

A magnetic tunnel junction magnetoresistive read head has one fixed ferromagnetic layer and one generally rectangularly shaped sensing ferromagnetic layer on opposite sides of the tunnel barrier layer, and a biasing ferromagnetic layer located around the side edges and back edges of the sensing ferromagnetic layer. An electrically insulating layer separates the biasing layer from the edges of the sensing layer. The biasing layer is a continuous boundary biasing layer that has side regions and a back region to surround the three edges of the sensing layer. When the biasing layer is a single layer with contiguous side and back regions its magnetic moment can be selected to make an angle with the long edges of the sensing layer. In this manner the biasing layer provides both a transverse bias field to compensate for transverse ferromagnetic coupling and magnetostatic coupling fields acting on the sensing layer to thus provide for a linear response of the head and a longitudinal bias field to stabilize the head. The biasing layer may also be formed with discrete side regions and a back region.

Description

The magnetic tunnel junction magnetoresistive read head that the vertical and horizontal bias voltage is arranged
Technical field
The application and sequence number are 09/087,553, exercise question is that " its free ferromagnetic has the magnetic tunnel junction memory cell of in-stack biasing and adopts the storage array of this unit " and sequence number are 09/087,334, exercise question is relevant for the application of " the magnetic tunnel-junction magnetoresistive transducer that has in-stack biasing ", and the two is all submitted to simultaneously with the application.
The present invention is usually relevant with magnetic tunnel-junction (MTJ) device, and is more specifically, relevant with the MTJ device that has the vertical and horizontal biasing that is used as magnetic resistance (MR) magnetic head that reads the magnetic recording data.
Background technology
A magnetic tunnel-junction (MTJ) device comprises two ferromagnetic layers that separated by a thin insulating tunnel barrier layer and based on spinning polarized electron tunnelling phenomenon.One of them ferromagnetic layer has higher saturated field intensity on a direction of externally-applied magnetic field, be in typical case since its coercive force than another ferromagnetic layer height.The quantum mechanics tunnelling can take place in enough thin the making of insulating tunnel barrier layer between two ferromagnetic layers.The tunnelling phenomenon is relevant with electron spin, makes that the magnetic response of MTJ is the relative orientation of two ferromagnetic layers and the function of spin polarization.
The MTJ device once was proposed the storage unit that is used as solid-state memory at first.The state of mtj memory cell is determined by measuring when the MTJ resistance of sense current when a ferromagnetic layer vertically arrives another ferromagnetic layer by MTJ.The charge carrier tunnelling is decided by the relative collimation of the magnetic moment (direction of magnetization) of two ferromagnetic layers by the probability of insulating tunnel barrier layer.Tunnelling current is spin polarization, and meaning is promptly from one of ferromagnetic layer, and for example, the magnetic moment of this layer is that fix or non-rotary, and the electric current that flows through mainly constitutes (spin is decided on the magnetic moment orientation of ferromagnetic layer up or down) by a kind of electronics of the type that spins.The degree of tunnelling current spin polarization is by being positioned at the electrovalence band structure decision that ferromagnetic layer and tunnel barrier layer constitute the magnetic material of ferromagnetic layer at the interface.Therefore first ferromagnetic layer is equivalent to a spin-filter.What of electronic state with spin polarization the same with the spin polarization of electric current in second ferromagnetic layer the probability of charge carrier tunnelling depend on.Usually, if the magnetic moment of the magnetic moment of second ferromagnetic layer and first ferromagnetic layer is parallel, so available electronic state is many during just than the magnetic moment antiparallel of the magnetic moment of second ferromagnetic layer and first ferromagnetic layer.Like this, the tunnelling probability of charge carrier is the highest when two-layer magnetic moment is parallel, and minimum when the magnetic moment antiparallel.Neither parallel neither antiparallel the time, tunnelling probability be got intermediate value when the orientation of magnetic moment.Therefore, the resistance of mtj memory cell depends on the spin polarization of electric current and the electronic state in two ferromagnetic layers.As a result, its direction of magnetization do not have two kinds of possible direction of magnetization of unique fixing ferromagnetic layer just to define two kinds of storage unit may position states (0 or 1).
Magnetic resistance (MR) sensor is surveyed field signal by the impedance variation of a sensing element of being made by magnetic material, and impedance variation is the intensity of the magnetic flux experienced of sensing element and the function of direction.Common MR sensor, for example those are used for the sensor of reading of data as the MR playback head in the magnetic recording disk driver, and its work is based on anisotropic magnetoresistive (AMR) effect of body magnetic material, and typical material is permalloy (Ni 81Fe 19).The one-component of read element resistance is along with the cosine of the angle between the direction of the direction of magnetization of read element and the sense current by read element square changes.The data of record can read from magnetic medium, the disk in the disc driver for example, because the external magnetic field (signal field) that is produced by magnetic recording medium makes the direction of magnetization in the read element change, and then causes the changes in resistance of read element and the variation of corresponding sense current or voltage.In traditional MR reading magnetic head, opposite with the MTJ device, the direction of sense current is parallel with the ferromagnetic layer in the read element.
Also once advised the MTJ device is used as magnetic resistance (MR) reading magnetic head of magnetic recording,, introduced in 061 as U.S. Patent No. 5,390.But, adopt one of problem of this MR magnetic head, be to develop a kind of suitable structure and make the output signal of device and magnetic field intensity that magnetic recording media produces is linear and be a kind of magnetic stabilizer spare.For the unusual difficulty of the MTJ device that obtains having linear response, because, not resembling the AMR sensor, current vertical so just provides any lateral offset field to ferromagnetic sensing layer by ferromagnetic layer and tunnel barrier.Like this, probe field is had linear response, just must take other means suitable lateral offset to be provided for the ferromagnetic sensing layer of mtj sensor in order to make mtj sensor.In addition, must take measures also to guarantee that ferromagnetic sensing layer remains on single domain state.If do not take this measure, in ferromagnetic sensing layer, may form many domain state, can produce the signal-to-noise characteristic of noise and then reduction device like this, and, may cause device that the response of probe field is not had repdocutbility.By providing the longitudinal biasing field device can be stabilized in a single basically domain state.The U.S. Patent No. 5,729,410 of IBM has been introduced a kind of MTJ MR reading magnetic head that adopts ferromagnetic material that sensing ferromagnetic layer is carried out longitudinal stability or biasing, and wherein bias material is placed on the outside of MTJ lamination and separates by electrically insulating material and lamination.
Needed MTJ MR reading magnetic head is to obtain linear output signal and to provide stable output signal to come its performance is optimized by the longitudinal biasing field by control lateral offset field.
Summary of the invention
The present invention is a MTJ MR reading magnetic head, and it has a fixed ferromagnetic layer and a sensing ferromagnetic layer that is generally rectangle of the relative both sides that are placed on tunnel barrier layer, and round the lateral edges and the antemarginal magnetism bias iron layer of sensing ferromagnetic layer.To the setover edge of layer and sensing layer of electric insulation layer is separated.Biasing layer is the biasing layer of a continuum boundary, and it has side direction part and back to part, three surrounded by edges of sensing layer can be got up.When biasing layer when being a side direction part with adjacency and back, its magnetic moment can be chosen as with the long limit of sensing layer angled to the individual layer of part.Biasing layer can provide simultaneously and be used for compensating the horizontal ferromagnetic coupling that is applied on the sensing layer and magnetostatic coupled field so that for MTJ MR reading magnetic head provides the lateral offset field of linear response like this, and the longitudinal biasing field that is used for stablizing magnetic head.The biasing layer can also constitute to part with discrete side direction part and back.Discrete side direction part may have and the magnetic moment orientation of back to the magnetic moment different directions of part, so that the horizontal and vertical bias-field of correct combination is provided.
According to an aspect of the present invention, provide a kind of magnetic tunnel device that links to each other with sensing circuit, be used for changes in resistance in the sensitive detection parts, this device comprises: a substrate; First conductive lead wire that is made on the substrate; A magnetic tunnel-junction lamination that is made on first lead-in wire, comprise one at the fixed ferromagnetic layer that does not have to have under the situation of externally-applied magnetic field fixed magnetic moment, one and the contacted insulating tunnel barrier layer of fixed ferromagnetic layer, and one and the contacted sensing ferromagnetic layer of insulating tunnel barrier layer, sensing ferromagnetic layer is generally rectangle, and a long backward dege edge lateral edge relative with two, that lack some is arranged; One and contacted second conductive lead wire of magnetic tunnel-junction lamination; One be made on the substrate, round the above-mentioned back of sensing ferromagnetic layer to lateral edge and with this back to the separated magnetism bias iron layer of lateral edge, the magnetic moment of magnetism bias iron layer is used for not having under the situation of externally-applied magnetic field the magnetic moment with sensing ferromagnetic layer be biased in a preferred direction, magnetism bias iron floor wherein comprise two near two lateral edge that lay respectively at sensing ferromagnetic layer lateral section and above-mentioned backward dege edge that is positioned at sensing ferromagnetic layer near back to the district, wherein the orientation of the magnetic moment of lateral section is different to the orientation of the magnetic moment of distinguishing with the back; One with magnetism bias iron layer and sensing ferromagnetic layer in the above-mentioned back of sensing ferromagnetic layer to the lateral edge place separately, discontiguous electrical insulator layer each other, insulation course wherein also with two lateral section and back to distinguishing; In view of the above, when electrical lead with after sensing circuit links to each other, vertical current is crossed the resistance of electric current of each layer of above-mentioned lamination by the relative orientation decision of the magnetic moment of fixing and sensing ferromagnetic layer, and sense current can avoid bypass to enter above-mentioned magnetism bias iron layer.
Preferably, in above-mentioned magnetic tunnel device, the magnetic moment of described magnetism bias iron layer is in the plane of this layer, it is oriented in greater than-90 degree less than between+90 degree, wherein 0 degree is consistent with the longitudinal direction that is parallel to for the backward dege edge of the sensing ferromagnetic layer of rectangle, and along in the magnetic moment direction that does not have sensing layer under the situation of externally-applied magnetic field.
Preferably, in above-mentioned magnetic tunnel device, the orientation of the magnetic moment of described fixing and sensing ferromagnetic layer is orthogonal not having under the situation of externally-applied magnetic field.
Preferably, in above-mentioned magnetic tunnel device, described insulation course is also with magnetism bias iron layer and at least one above-mentioned conductive lead wire electrical isolation.
Preferably, in above-mentioned magnetic tunnel device, described first conductive lead wire is a bottom lead, and the magnetic tunnel-junction lamination is made in and makes on the substrate that the fixed ferromagnetic layer and first conductive lead wire are conductings, second conductive lead wire is a top lead, electrically contacts with sensing ferromagnetic layer.
Preferably, in above-mentioned magnetic tunnel device, described first conductive lead wire is a bottom lead, and the magnetic tunnel-junction lamination is made in and makes on the substrate that the sensing ferromagnetic layer and first conductive lead wire are conductings, second conductive lead wire is a top lead, electrically contacts with fixed ferromagnetic layer.
Preferably, in above-mentioned magnetic tunnel device, that all of described above-mentioned lamination layer all adopt is same, have the extrorse rectangle of sides adjacent.
Preferably, in above-mentioned magnetic tunnel device, described magnetic tunnel-junction lamination also comprise one with the contacted inverse ferric magnetosphere of fixed ferromagnetic layer, be used for the magnetic moment of fixed ferromagnetic layer being fixed on preferred direction by interface exchange coupling.
Preferably, in above-mentioned magnetic tunnel device, described magnetism bias iron layer is by comprising Co, and the alloy of Pt and Cr is made.
Preferably, in above-mentioned magnetic tunnel device, described magnetism bias iron layer comprises a ferromagnetic thin film and an antiferromagnet film that contacts and carry out interface exchange coupling with above-mentioned ferromagnetic thin film.
Preferably, in above-mentioned magnetic tunnel device, described ferromagnetic thin film is made of the alloy of a kind of Ni and Fe, and antiferromagnet film wherein is made of the alloy of a kind of Ni and Mn.
According to another aspect of the present invention, provide a kind of magnetic tunnel-junction magnetic resistance reading magnetic head that is used for surveying the data that are recorded on the magnetic medium, magnetic head has the sensing surface of facing with medium, comprising: a substrate; Along the general direction vertical with sensing surface, making is having under the externally-applied magnetic field situation that comes from medium regularly for a fixed ferromagnetic layer that is made on the substrate, the direction of magnetization of fixed ferromagnetic layer, and direction of magnetization is not rotated basically; An insulating tunnel barrier layer that is positioned on the fixed ferromagnetic layer and is in contact with it; A sensing ferromagnetic layer that is positioned on the tunnel barrier layer and is in contact with it, its magnetization orientation is along the general preferred orientations parallel with sensing surface, and usually the direction of magnetization of the fixed ferromagnetic layer when not having externally-applied magnetic field is vertical, and come from existence under the situation of externally-applied magnetic field of medium, direction of magnetization can rotate freely, sensing ferromagnetic layer is generally rectangle, its long sensing edge is parallel with sensing surface, its long backward dege edge is parallel with sensing edge, and two weak points some, relative lateral edge; One be made on the substrate, round the above-mentioned back of sensing ferromagnetic layer to lateral edge and with this back to the separated magnetism bias iron layer of lateral edge, be used for not having under the situation of externally-applied magnetic field direction of magnetization be biased in above-mentioned preferred direction with sensing ferromagnetic layer, magnetism bias iron floor wherein comprise two near two lateral edge that lay respectively at sensing ferromagnetic layer lateral section and above-mentioned backward dege edge that is positioned at sensing ferromagnetic layer near back to the district, wherein the orientation of the magnetic moment of lateral section is different to the orientation of the magnetic moment of distinguishing with the back; One between biasing and sensing ferromagnetic layer, be used for a electric insulation layer with biasing layer and sensing layer insulation, insulation course wherein also with two lateral section and back to distinguishing; A pair of electrical lead, each lead-in wire links to each other with one of sensing layer with fixed bed respectively, and by insulation course and biasing layer electrical isolation, in view of the above, when sense current was flowed through between two lead-in wires, electric current vertically passed the insulating tunnel barrier layer usually and do not enter the biasing layer.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, also comprise one and the contacted inverse ferric magnetosphere of fixed ferromagnetic layer, it fixes the direction of magnetization of fixed ferromagnetic layer by interface exchange coupling.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, first of above-mentioned conductive lead wire is made on the substrate, and inverse ferric magnetosphere wherein is made on the substrate, between substrate and fixed ferromagnetic layer, fixed ferromagnetic layer is made on the inverse ferric magnetosphere and with it and contacts, and in view of the above, the direction of magnetization of fixed ferromagnetic layer can fix by the interface exchange coupling with inverse ferric magnetosphere.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, first of described conductive lead wire is made on the substrate, and sensing layer wherein is between first conductive lead wire and insulating tunnel barrier layer.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, described fixed ferromagnetic layer, tunnel barrier layer and sensing ferromagnetic layer are made a lamination, the edge of fixed ferromagnetic layer and tunnel barrier layer and the rectangular edges of sensing ferromagnetic layer are coplanes, and insulation course wherein is with above-mentioned lamination and magnetism bias iron layer and the insulation of above-mentioned conductive lead wire.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, the direction of magnetization of described magnetism bias iron layer is in the plane of this layer, it is oriented in greater than-90 degree with less than between+90 degree, wherein, 0 degree is consistent with the longitudinal direction that is parallel to for the backward dege edge of the sensing ferromagnetic layer of rectangle, and along in the direction of magnetization that does not have sensing layer under the situation of externally-applied magnetic field.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, described magnetism bias iron layer is by comprising Co, and the alloy of Pt and Cr is made.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, described magnetism bias iron layer comprises a ferromagnetic thin film and an antiferromagnet film that contacts and carry out interface exchange coupling with above-mentioned ferromagnetic thin film.
Preferably, in above-mentioned magnetic tunnel-junction magnetic resistance reading magnetic head, described ferromagnetic thin film is made of the alloy of a kind of Ni and Fe, and antiferromagnet film wherein is made of the alloy of a kind of Ni and Mn.
Essence for a more complete understanding of the present invention and advantage, the detailed introduction that can provide with reference to following related accompanying drawing.
Description of drawings
Fig. 1 is the simplification calcspar that is used for according to traditional magnetic recording disk driver of MTJ MR reading magnetic head of the present invention.
Fig. 2 is the top view after the disc driver among Fig. 1 removes top cover.
Fig. 3 is the vertical cross-section that traditional integrated form is responded to write head/MR reading magnetic head, and it is middle and adjacent with the induction write head that the MR reading magnetic head is placed on screen layer.
Fig. 4 is used for according to the magnetic tunnel junction layer of MTJ MR reading magnetic head of the present invention and the xsect of conductive lead wire.
Fig. 5 A and Fig. 5 B are the top view and the cross-sectional views of the MTJ reading magnetic head of prior art, have the longitudinal biasing district that is electrically insulated from each other on the left side and the right side of MTJ device.
Fig. 6 is the top view of the MTJ reading magnetic head of the prior art among Fig. 5, shows the layout of MTJ reading magnetic head with respect to air bearing surface.
Fig. 7 shows by that peg or fixing ferromagnetic layer and is applied to ferromagnetic coupling field and magnetostatic coupled field on the MTJ sensing layer.
Fig. 8 is the top view of MTJ MR reading magnetic head of the present invention, and it has the ferromagnetic bias area that the vertical and horizontal bias-field can be provided in three sides of tunnel junction.
Fig. 9 is the top view of MTJ MR reading magnetic head of the present invention, it has the ferromagnetic bias area of separation in three sides of tunnel junction, wherein a bias area at tunnel junction backward dege edge provides the lateral offset field, and provides a longitudinal biasing field at the separating part of tunnel junction side direction.
Figure 10 A shows making step according to the MTJ MR reading magnetic head of the present invention of Fig. 8 to 10E.
Figure 11 A shows making step according to the MTJ MR reading magnetic head of the present invention of Fig. 9 to 11E.
Embodiment
At first, wherein show the schematic sectional view that a class adopts the prior art disc driver of MR sensor with reference to Fig. 1.Disc driver comprises a pedestal 10, has fixed a disc driver motor 12 and a driver 14 and a top cover 11 on it.Pedestal 10 and top cover 11 provide a sealed space basically for disc driver.In typical case, an O-ring seal 13 is arranged between pedestal 10 and top cover 11, and a little air hole (not shown) is arranged, be used for the pressure of balance disk driver interior and external environment condition.By movement 18 magnetic recording disk 16 is linked to each other with drive motor 12, disk can rotate by drive motor 12 with after movement links to each other.Apply the thin lubricating film 50 of one deck on the surface of disk 16.At carriage, for example the tail end of an air bearing slider 20 is done a read/write magnetic head or converter 25.Converter 25 is one and comprises writing/reading magnetic head of an induction write head district and a MR reading magnetic head district, will be introduced it according to Fig. 3.Slider 20 links to each other with driver 14 with suspension 24 by a rigid arm 22.Suspension 24 provides a bias force of slider 20 being shifted onto the surface of recording disc 16.In the process of disc driver operation, drive motor 12 is rotated disk 16 with fixed speed, and driver 14, the voice coil motor (VCM) of linear pattern or annular typically, generally radially mobile slider 20, make its surface of crossing disk 16, read/write magnetic head 25 just can touch the different pieces of information road of disk 16 like this.
Fig. 2 is the top view that removes the inside of the disc driver behind the top cover 11, illustrates in greater detail suspension 24, and the power that it provides is pushed slider 20 to disk 16.Suspension can be the suspension of traditional type, and for example well-known Watrous suspension is introduced in the U.S. Patent No. 4,167,765 as IBM.Such suspension also provides gimbal-mounted connection for slider, and making that slider is suspended on the air bearing can pitching and vacillate now to the left, now to the right.The data of being surveyed from disk 16 by converter 25 are installed in signal the integrated circuit (IC) chip 15 on the arm 22 and amplify and become a data readback signal with processing circuit processes.The signal of converter 25 is passed to chip 15 by flexible cable 17, and chip 15 is given its output signal the electronic circuit (not shown) of disc driver by cable 19.
Fig. 3 is the cross sectional representation of an integrated read/write magnetic head 25, and it comprises a MR reading magnetic head district and an induction write head district.Magnetic head 25 forms an air bearing surface (ABS) by polishing, and as discussed above, ABS separates by the surface of air bearing and spinning disk 16 (Fig. 1).Reading magnetic head comprises a MR sensor 40 that is clipped between first and second gap layer G 1 and the G2, and they are clipped in again between the first and second magnetic masking layer S1 and the S2.In traditional disc driver, the MR sensor is an AMR sensor.Write head comprises a coil layer C and insulation course 12, and they are clipped between insulation course 11 and 13, and these two insulation courses are clipped in again between the first and second pole piece P1 and the P2.Extreme place near two pole pieces of ABS at the first and second pole piece P1, clips a gap layer G 3 between the P2, be used to provide a magnetic gap.In ablation process, among the marking current lead-in wire ring layer C, to first and second utmost point layer P1, among the P2, make flux concentration near ABS place extreme flux sensing.In write operation, this magnetic flux can be with the loop turn magnetization of rotating disk 16.In read operation, the magnetized area on the rotating disk 16 imports magnetic flux in the MR sensor 40 of reading magnetic head, makes the impedance of MR sensor 40 change.These impedance variation can be surveyed by detecting the change in voltage in the MR sensor 40.Change in voltage is handled the rear drive electronic circuit and is converted user data to through chip 15 (Fig. 2).Combined head 25 shown in Figure 3 is " merging " formula magnetic heads, and wherein the secondary shielding layer S2 of reading magnetic head is used as the first pole piece P1 of write head.Carry on the back in the back of the body formula magnetic head (not shown) at one, the secondary shielding layer S2 and the first pole piece layer P1 separate.
Above about the introduction of the magnetic recording disk driver that typically has the AMR reading magnetic head, and accompanying drawing 1 to 3, just for illustrative purposes.Disc driver may comprise many disks and driver, and each driver can be supported many sliders.In addition, head carriage can not adopt the air bearing slider, a kind ofly magnetic head is kept in touch or near the slider that contact with disk but adopt, for example the contact of liquid contact or other type or near the recording disc driver that contacts.
Fig. 4 shows the MTJ MR reading magnetic head of the prior art of a mtj sensor that has a MR sensor 40 in the read/write magnetic head 25 that is used for replacing among Fig. 3.On a suitable substrate 9, formed a bottom electrical lead-in wire 102.Substrate can be that gap layer G 1 or go between 102 can directly form on magnetic masking layer S1.Mode with lamination forms MTJ100 between bottom electrical lead-in wire 102 and top electrical lead 104 then.The top electrical lead can be with screen layer S2 electrical isolation or is directly linked to each other with screen layer S2 to constitute the part of MTJ device electronic circuit.
MTJ100 comprises the tunnel barrier layer 120 of first or multilayer laminated 110, one insulation of bottom electrode, and one second or top electrodes lamination 130.Each electrode comprises one and tunnel barrier layer 120 direct-connected ferromagnetic layers, i.e. ferromagnetic layer 118 and 132.
Comprise initial or " model " layer 112 that is made on the lead-in wire 102 at the polar stack 110 that forms on the electrical lead 102, one deck antiferromagnet 116 that is made on the model layer 112, and on inverse ferric magnetosphere 116 of doing below and with " fixing " ferromagnetic layer 118 of inverse ferric magnetosphere exchange coupling.It is that its magnetic moment or direction of magnetization can not rotated because at needed scope internal memory during at externally-applied magnetic field that ferromagnetic layer 118 is called as fixed bed.Top electrodes lamination 130 comprises one " freely " or " sensing " ferromagnetic layer 132 and a protection or an overlayer 134 that is formed on the sensing layer 132.Sensing ferromagnetic layer 132 not with an inverse ferric magnetosphere exchange coupling, therefore when at needed scope internal memory during at externally-applied magnetic field, its direction of magnetization can rotate freely.The making of sensing ferromagnetic layer 132 makes not to be had under the situation of externally-applied magnetic field, and the orientation of its magnetic moment or direction of magnetization (being illustrated by arrow 133) is general parallel with ABS, and (ABS is a plane parallel with the paper among Fig. 4; See Fig. 3 again) and usually vertical with the direction of magnetization of fixed ferromagnetic layer 118.Just in time be arranged in the fixed ferromagnetic layer 118 of the polar stack 110 below the tunnel barrier layer 120, by with its inverse ferric magnetosphere that is close to below 116 interface exchange coupling taking place its direction of magnetization is fixed, this fixed ferromagnetic layer also is the part of bottom electrode stack 110.The orientation of the direction of magnetization of fixed ferromagnetic layer 118 is general vertical with ABS, promptly passes or enter paper (shown in arrow end 119) from the paper Fig. 4.
Fig. 5 A and Fig. 5 B show the cut-open view and the top view of the MTJ MR reading magnetic head among Fig. 4 respectively, wherein added a magnetization in addition and carried out the magnetism bias iron layer 150 of longitudinal biasing and one insulation course 160 that other layer of layer 150 and sensing ferromagnetic layer 132 and MTJ 100 separate and isolate of will setovering sensing ferromagnetic layer 132.Device among Fig. 5 A-B has more detailed introduction in the U.S. Patent No. 5,729,410 of IBM.Magnetism bias iron layer 150 is by retentive material, and for example the CoPtCr alloy constitutes, and magnetic moment 133 collimations of its magnetic moment (being illustrated by arrow 151) sensing ferromagnetic layer 132 when not having externally-applied magnetic field are on same direction.Insulation course 160 is preferably aluminium oxide (Al 2O 3) or monox (SiO 2), its thickness is enough to magnetism bias iron layer 150 and MTJ100 and electrical lead 102,104 electrical isolations, but still is thinned to permission and the magnetostatic coupling of sensing ferromagnetic layer 132 generations.The product M*t of magnetism bias iron layer 150 (wherein M is the magnetic moment of the material unit area in the ferromagnetic layer, and t is the thickness of ferromagnetic layer) must be bigger or equal than the M*t of sensing ferromagnetic layer 132, could guarantee stable longitudinal biasing.Because sensing ferromagnetic layer 132 normally used Ni (100-x)-Fe (x)The magnetic moment of (x is about 19) is about the typical retentive material that is suitable for magnetism bias iron layer 150, for example Co 75Pt 13Cr 12The twice of magnetic moment, the thickness of magnetism bias iron layer 150 is at least about the twice of the thickness of sensing ferromagnetic layer 132.
Fig. 6 is the top view of the MTJ MR magnetic head shown in Fig. 5 B equally, but it shows the configuration of MTJ magnetic head with respect to ABS.On behalf of ABS and MTJ MR magnetic head, dotted line 161 carry out that root line of back each layer and its overlap joint.MTJ 100 is painted as the band of a width TW, adapts with the road of disk identifying recording layer is wide, and the final swath height behind the overlap joint is SH.The width in record data road is wideer than TW in typical case.Notice for purpose clearly we with reference to the edge of mtj sensor, on it deposit as the longitudinal biasing district 150 of left side and right side edge 180.
Sense current I flows out from first contact conductor 102, vertically passes inverse ferric magnetosphere 116, fixed ferromagnetic layer 118, and tunnel barrier layer 120, and sensing ferromagnetic layer 132 flow out by second contact conductor 104 then.As previously mentioned.The size of tunnel current of barrier layer 120 of passing through tunnel is adjacent with tunnel barrier layer 120 and the function of the relative magnetization orientation of the fixing and sensing ferromagnetic layer 118,132 that is in contact with it.The magnetic field that is produced by record data makes the direction of magnetization of sensing ferromagnetic layer 132 rotate offset direction 133, promptly enters or pass the paper among Fig. 4.This just changed ferromagnetic layer 118,132 magnetic moment relative orientation thereby changed the size of tunnel current, this change is reflected in the variation in MTJ 100 resistance.The data of reading back from disk are surveyed and be processed into to this changes in resistance by the electronic circuit of disc driver.This sense current is because electrical insulator layer 160 and can't arrive magnetism bias iron layer 150, and this insulation course insulation course 150 of also will setover insulate with electrical lead 102,104.
The existence in longitudinal biasing district 150 makes the ferromagnetic sensing layer of MTJ be stabilized in single domain state basically among Fig. 5 A-5B and Fig. 6.If there is not bias area 150, the magnetic pole that appears at 180 places, edge of sensing layer 132 so might cause forming closure domain in these edges very much.The signal that many domain state of sensing layer will further produce noise and can't repeat original same probe field generation.
Preferred embodiment
Closure domain can be eliminated to guarantee the operate as normal of MTJ reading magnetic head by the longitudinal biasing district, and in addition, it is linear also having requirement response of magnetic head in the probe field that adds.This point can realize by the magnetic moment of lateral offset sensing layer 132 suitably.Without any the static state that adds probe field, the best configuration of MTJ reading magnetic head is, the magnetic moment orientation of sensing layer 132 is parallel with ABS161 basically and the magnetic moment with that peg or fixing ferromagnetic layer 118 is vertical basically.The magnetic moment orientation of fixed ferromagnetic layer 118 is vertical with ABS basically.Under these conditions, the arrangement of the magnetic moment of sensing layer makes the MTJ device have maximum sensitivity to probe field, because the tunneling conductance of MTJ device is varies with cosine along with the angle of the magnetic moment direction of sensing layer 132 and fixed bed 118.And inclined to one side by the maximum angular of the magnetic moment that adds the sensing layer that probe field causes before the tunneling conductance of device is saturated, the situation that the direction of probe field is either parallel or anti-parallel to the normal of ABS all is the same.
As shown in Figure 7.Sensing layer 132 has 182, one backward dege edge 190 of forward edge and a lateral edge 180 in the face of ABS.When adding probe field, the magnetic moment orientation of sensing layer 132 is by the clean Equivalent Magnetic Field decision that acts on the sensing ferromagnetic layer.Anticipate as shown in Figure 7, this mainly is any ferromagnetic coupling field H between sensing layer 132 and the fixed ferromagnetic layer 118 FWith mainly produce by the magnetic pole at 185 places, edge of fixed ferromagnetic layer, act on the magnetostatic coupled field H on the sensing layer DBetween the result of balance.In addition, sensing layer 132 can show certain magnetic anisotropy, and the magnetic moment that helps sensing layer like this is orientated along the specific direction in the sensing layer plane.This magnetic anisotropy may come from the intrinsic magnetocrystalline anisotropy of the ferromagnetic material that constitutes sensing layer, perhaps may obtain by deposit sensing ferromagnetic layer in magnetic field or by being inducted by the magnetostriction of the sensing layer of the stress in the sensing layer (for example introducing in the processing procedure of MTJ device) generation.In addition, may there be the magnetic shape anisotropy from static magnetic field certain, that come from sensing layer.
Magnetostatic coupled field H DCan change by thickness or the magnetic moment that changes fixed ferromagnetic layer, perhaps constituting fixed ferromagnetic layer by the sandwich structure that adopts antiferromagnetic coupling changes, this sandwich structure comprises two ferromagnetic layers that separated by a thin antiferromagnetic coupling layer, as submitting on July 16th, 1997, the pending application No.08/895 of IBM is introduced in 118.Ferromagnetic coupling field H FCan change by introduce a thin non-ferromagnetic layer between tunnel barrier layer 120 and ferromagnetic sensing layer 132, as submitting on November 27th, 1996, the pending application No.08/758 of IBM is introduced in 614.But adopt other non-ferromagnetic layer will reduce the amplitude of the magnetic tunnelling response of MTJ device.And more complicated MTJ device 100 that may be difficult to more make of these methods needs, and the additional deposit source that is used for extra play that may need possibly to obtain.In addition, the magnetic moment of sensing layer (thereby its thickness) can be fixed by the density of the magnetic bit (bit) that writes down, and the performance of magnetic recording reading magnetic head is best like this.
In traditional MR device, a complementary field that acts on the ferromagnetic sensing layer is arranged, this magnetic field is to be produced by the electric current of each layer that is parallel to magnetic device.On the contrary, electric current is vertically to pass through ferromagnetic layer in the MTJ device, thereby produces an insignificant transverse magnetic field on sensing layer.Like this, in the MTJ device, need a kind of mechanism that additional transverse magnetic bias-field is provided, to guarantee the just bias of MTJ device.As shown in Figure 8, this lateral offset field is provided by a ferromagnetic biasing layer 320, it has longitudinal biasing district 322 (as shown in Figure 7) near the left side of sensing layer 132 and right side edge 180, along the backward dege edge 190 that leaves the ABS plane lateral offset district 324 is arranged.Biasing layer 320 will be called as continuum boundary biasing (CBB) layer.The forward edge 182 of the sensing layer of MTJ device 100 promptly is in the edge at ABS place, is not capped, and the magnetic flux that is produced by the record cell in the magnetic medium can be surveyed by sensing layer like this.The forward edge of mtj sensor can directly be placed on the ABS place or can fall in from ABS as among Fig. 8, and flux can be directed to the forward edge that falls in of sensor by the flux guide groove.Adopt additional bias area 324 can produce the lateral offset field of moderate range (the indicated direction of arrow 382 in Fig. 8) at backward dege edge 190.In addition, become tiltedly, depart from the ABS in the thin film planar by direction with the magnetic moment of CBB layer 320, indicated as the arrow among Fig. 8 380, add a longitudinal biasing field (direction of arrow 384 in Fig. 8) can for MTJ 100.By suitable adjustment tiltangle, the amplitude of the lateral offset field that is produced by CBB layer 320 can change arbitrarily in a specific scope, can obtain like this being added in the transverse field H on the ferromagnetic sensing layer of MTJ DAnd H FMore fully compensation.Simultaneously, CBB layer 320 provides the longitudinal biasing field that mtj sensor is stablized in enough being used for.The direction 380 of magnetic moment can be between between+/-90 degree, and wherein 0 degree is corresponding to consistent with the magnetic moment direction of parallel pure longitudinal direction in the long limit of rectangle sensing layer 132 and the sensing layer when not having externally-applied magnetic field.Choose suitable angle θ and can guarantee to be used for the compensate for lateral field simultaneously with the lateral offset that obtains linear response and be used for stable longitudinal biasing.
As shown in Figure 9, in another embodiment, CBB layer 425 can be made three different parts, in two longitudinal biasing districts 420 of the side of the sensing ferromagnetic layer of MTJ 100, and the lateral offset district 425 of the back side or back.The longitudinal biasing field is provided by the left side of MTJ 100 and the bias area 420 at right side edge 180 places, but the bias area that is in backward dege edge 190 places in the present embodiment is made into a discrete areas 425.Such two bias areas 420 and 425 magnetic moment can independent design to provide intensity and direction all suitable horizontal and vertical bias-field.In simple embodiment, the direction of horizontal and vertical bias area 420 and 425 magnetic moment is along a common pitch angle orientation, the direction that arrow in Fig. 9 480 is indicated.Arrow 484 and the 482 indicated directions of vertical and horizontal bias-field in Fig. 9 like this.In another embodiment, wherein lateral offset part 425 and longitudinal biasing part 420 are made of the ferrimagnet of different hardness or high coercivity, the tiltangle in lateral offset district 425 TTiltangle with longitudinal biasing district 420 LCan get different pitch angle.
Introduce the one group of representational material that is used for MTJ 100 (Fig. 4) below.All layers of MTJ 100 all are along growing under the condition that is parallel to substrate surface and has externally-applied magnetic field.Magnetic field is used for the easy magnetizing axis of all ferromagnetic layers is orientated.At first form the Ta inculating crystal layer (not shown) of a 5nm on as the Au layer of the 10-50nm of electrical lead 102.Inculating crystal layer is by a kind of face-centered cubic (fcc) Ni that promotes 81Fe 19The material of (111) growth of model layer 112 constitutes.Model ferromagnetic layer 112 can promote the growth of inverse ferric magnetosphere 116.Suitable inculating crystal layer material comprises the fcc metal, the combination of for example Cu, and Ta or these layers, for example 3-5nmTa/3-5nmCu.MTJ base electrode lamination 110 comprises a 4nm Ni on the Ta inculating crystal layer on the Au layer 102 that is grown in 10-20nm 81Fe 19/ 10nm Fe 50Mn 50/ 8nm Ni 81Fe 19The lamination of (being respectively layer 112,116,118).Au trace layer 102 is formed on the aluminium oxide clearance material G1 as substrate.Then, by deposit then the Al layer of a 0.5-2nm of plasma oxidation form tunnel barrier layer 120.So just made Al 2O 3Insulating tunnel barrier layer 120.Top electrodes lamination 130 is laminations (being respectively 132,134 layers) of a 5nmNi-Fe/10nmTa.Ta layer 134 is used as the tin hat cap rock.Top electrodes lamination 130 contacts with a 20nmAu layer as electrical lead 104.
Notice that because current vertical flows through each layer of MTJ 100, the impedance of MTJ 100 will mainly be contributed by tunnel barrier layer 120.Like this, the impedance of conductive lead wire 102,104 per unit areas may be high more a lot of than traditional MR reading magnetic head, and parallel each laminar flow of electric current is moving in traditional MR magnetic head.Therefore, lead-in wire 102,104 can be done thinlyyer and/or narrower than the lead-in wire in traditional MR magnetic head structure, and/or can adopt the higher material of intrinsic impedance, as the complex of alloy or element.
Each layer of bottom electrode stack 110 wanted smooth and Al 2O 3It is very important that tunnel barrier layer 120 does not have possibility to make the pinprick of tunnel junction short circuit.For example, the sputtering technology that can produce not only good but also strong magnetoresistance in the metallic multilayer lamination that employing is known is grown just enough.
Another sensing ferromagnetic layer 132 can be by the Co at the interface or the Co that are between sensing ferromagnetic layer 132 and the tunnel barrier layer 120 (100-x)Fe (x)Or Ni (100-x)Fe (x)(x is about 60) thin layer constitutes, and the body material of layer 132 is a kind of low magnetostriction material, for example Ni (100-x)Fe (x)(x is about 19).This class adopts thin Co or Co (100-x)Fe (x)Or Ni (100-x)Fe (x)The clean magnetostriction of the sensing layer of (x is about 60) contact bed changes the value that just can obtain near 0 a little by the constituent to 132 layers of body material.Another kind of fixed ferromagnetic layer 118 can be basically by the body material Ni (100-x)Fe (x)Layer constitutes, with tunnel barrier layer 120 a Co or Co arranged at the interface (100-x)Fe (x)Or Ni (100-x)Fe (x)(x is about 60) thin layer.Adopt the Co or the Ni of high polarization (100-x)Fe (x)(x is about 60) or Co (100-x)Fe (x)Alloy (x is about 70) can obtain maximum signal.The optimum thickness of contact bed is 1-2nm.The clean magnetostriction of composite bed can be by changing the value that obtains near 0 a little to constituent.If 118 layers body material is Ni-Fe, forming so is exactly Ni 81Fe 19, the Ni-Fe body material of this composition has zero magnetostriction.
Fe-Mn inverse ferric magnetosphere 116 can be replaced with Ni-Mn or Ir-Mn layer or other suitable inverse ferric magnetosphere, and they are can be to the ferromagnetic material in the fixed bed 118 exchange biased and have an Al of being far smaller than 2O 3The impedance of barrier layer 120.For example can adopt and have the antiferromagnetic oxide layer that enough electricity are led.In addition, the magnetic moment of fixed ferromagnetic layer is to fix by the interface exchange coupling with an inverse ferric magnetosphere in a preferred embodiment, and fixed ferromagnetic layer can adopt the high coercivity magnetic material of " firmly " to constitute, thereby has not just needed inverse ferric magnetosphere.Therefore, hard fixed ferromagnetic layer can adopt many kinds of ferromagnetic materials to make, for example the alloy of Co and one or more other elements, comprise the Co-Pt alloy, Co-Pt-Cr alloy, Co-Cr-Ta alloy, the Co-Cr alloy, Co-Sm alloy, Co-Re alloy, the Co-Ru alloy, Co-Ni-X alloy (X=Pt, Pd, or Cr), and many quaternary alloys, for example Co-Ni-Cr-Pt and Co-Pt-Cr-B.
The MTJ device of also introducing shown in Fig. 4 has fixed ferromagnetic layer in the bottom of MTJ 100, and this device also can pass through at first deposit sensing ferromagnetic layer, and then deposit tunnel barrier layer, fixed ferromagnetic layer and inverse ferric magnetosphere are made.Like this, each layer of this MTJ device is the inverted sequence of the MTJ 100 shown in Fig. 4 basically.
Make the technology of MTJ MR reading magnetic head of the present invention
At first introduce the technology of making the MTJ MR reading magnetic head that has CBB layer 320 of the present invention with reference to the process chart of Figure 10 A-10E.In this picture group, the top view that has only provided device is used for illustrating the necessary basic photoetching Butut step of the MTJ MR magnetic head shown in the construction drawing 8.
Technology each layer that constitutes MTJ 100 is not shown among Figure 10 A-10E, but this group layer will be called MTJ separately for convenience of explanation.The substrate (not shown) of each layer of deposit can be that G1 aluminium oxide clearance layer also can be screen layer S1 thereon.The magnetron sputtering technology of argon filling (Ar) gas is adopted in film growth, and substrate is in room temperature.Must carefully can make very level and smooth film to guarantee that sputter is grown.Can adopt an amplitude is the externally-applied magnetic field of 20-100Oe, and its direction is in the plane of substrate, and this magnetic field is used for introducing magnetic anisotropy when the growth ferromagnetic layer.As the part of the formation of MTJ 100, deposit will become the aluminium lamination of tunnel barrier layer 120, be that 100mTorr, power density are 25W/cm at oxygen pressure then 2Condition under, with plasma oxidation 30-240 second.This has just made the aluminium oxide tunnel barrier layer 120 of insulation.The plasma state oxidation of aluminium lamination is to carry out under the vacuum condition of not breaking technological process.
Although the work to the MTJ device is not basic, fixing and sensing ferromagnetic layer is introduced magnetic anisotropy and is benefited by deposit in the magnetic field of quadrature basically.Before the sensing ferromagnetic layer 132 of deposit MTJ100, and after forming aluminium oxide tunnel barrier layer 120, in substrate plane, substrate is rotated about 90 degree, make substrate roughly become horizontal with externally-applied magnetic field.Perhaps, can rotate externally-applied magnetic field.
When this technological process begins, sequential deposit bottom lead 102 and MTJ 100 (comprising top cap layer 134).Then these layers are patterned in the shape of bottom electrical lead-in wire 102, a part wherein has been shown among Figure 10 A.At next step, Figure 10 B adopts photolithography to form one and the corresponding open region 325 of continuum boundary bias area.This step can be by at first covering a photoresist layer 310 on MTJ 100, expose then and Butut is realized to form open region 325.This step also defines the wide TW in equivalent road as the MTJ 100 of formed open region 325 inside dimensions.Shown in Figure 10 B, on lead-in wire 102 and MTJ 100, covered the positive photoresist 310 of one deck, define wide TW after the development.Then, the material that will have the shape of layer 325 removes from MTJ 100 by ion etching, up to electrical lead layer 102.By the material of suitable selection cap layer 134 (Fig. 4), might carry out reactive ion etching to cap layer before carrying out etching at other layer to MTJ.
Next step, in Figure 10 C, by the initial alumina insulating layer 330 of open region 325 deposits in the photoresist layer 310, CoPtCr hard iron magnetic CBB layer 320, and alumina insulating layer subsequently 330, the bias material district that reserves an electrical isolation is used for constituting CBB floor 320.
Insulation course 330 adopts three kinds of different deposition process to form with hard ferromagnetic layer 320.At first, constitute the bottom of 330 floor and, the sidewall of MTJ 100 and head portion or each layer of rear wall or MTJ 100 (Fig. 4) are consistent with the first aluminium oxide illuvium according to the degree of depth of 325 districts ion etching.If radiofrequency sputter deposition technology has been adopted in the deposit of insulation course, the thickness of the insulation course of sidewall is just thin than a flat lip-deep insulation course so.Typical sputtering yield on sidewall is 1/2 or 3/4 of a flat lip-deep sputtering yield.In second step, what the deposit of hard magnetism bias iron layer 320 was adopted is directional deposition, for example ion beam deposition.Conformal deposited can be used to CBB layer 320 and MTJ 100 insulation at the sidewall of MTJ 100 and first oxide insulating layer of rear wall.In the 3rd step, the insulation course of last deposit has constituted 330 layers apex zone and covering or has sealed the top surface of CBB layer 320.
Initial sum alumina layer 330 subsequently preferably adopts radio-frequency sputtering to form, and makes each edge that covers electrical lead 102 and MTJ 100 fully to be 100-500 at these local thickness.This technology can cause one to have the very insulator of high integrality, because guarantee that it is very important that sense current can bypass pass CBB layer 320.CBB layer 320 is preferably the CoPtCr alloy, preferably adopts directional deposition, and for example ion beam sputter deposition constitutes, and does not so just have imbricate, and the thickness of deposit is about the twice of the thickness of sensing layer 132.In one is peeled off, photoresist layer 310 and aluminium oxide and hard bias layer on it are removed then, obtain a left side that is positioned at MTJ 100, the back to the continuum boundary bias area of the hard bias ferromagnetic layer 320 of the electrical isolation of right side edge.Figure 10 C shows the net result of this technology, for the sake of clarity shows the isolation edge of insulator.Next step adopts photoetching technique by photoresist layer 340 (Figure 10 D) being carried out the initial cut height (before the polishing) that deposit and Butut constitute MTJ 100.At last, unnecessary tunnel junction material is removed,, finish the making of the MTJ reading magnetic head shown in Figure 10 E up to electronic conductor layer 102 by ion etching.The making of MTJ MR magnetic head structure has just been finished basically like this, just needs the last electrical lead of making device.
In the process chart that Figure 10 A-10E provides, first lithography step (Figure 10 B) defines the width of sensor and sensor backward dege edge simultaneously.But the narrow back of adopting photoetching technique to limit a submicron-scale is the comparison difficulty to the zone, because the exposure light source in the photoetching process can't be fully the photo anti-corrosion agent material at shape 325 internal corners places is removed.In addition, this technological process only provides a single continuum boundary bias area 320, and meaning is that the intensity of horizontal and vertical bias-field can not independent variation but coupled to each other.In order to solve this two problems, Figure 11 A-11E shows improved technological process, and it has constituted the MTJ MR reading magnetic head shown in Fig. 9
Embodiment.
The desired technological process of MTJ MR reading magnetic head shown in Fig. 9 has illustrated in Figure 11 A-11E.Other lithography step of this technological requirement limits discrete backward dege edge lateral offset district 425.Equally, when technology is initial, sequential deposit bottom lead 102 and MTJ100 (comprising top cap layer 134).Then these layers are patterned in the shape of bottom electrical lead-in wire 102, a part wherein has been shown among Figure 11 A.In next step, Figure 11 B adopts photoetching technique to constitute two open regions 421, wherein in the left side of mtj sensor 100 and right side edge with deposit longitudinal biasing district.This step also defines the wide TW in equivalent road of MTJ 100.Shown in Figure 11 B, on lead-in wire 102 and MTJ 100, be coated with the photoresist layer 410 of one deck positivity, define wide TW after the development.Then, adopt ion etching from MTJ 100, the material in two shapes 421 to be removed, up to electrical lead layer 102.
Next step, in Figure 11 C, by the initial alumina insulating layer 430 of open region 421 deposits in the photoresist layer 410, CoPtCr hard bias ferromagnetic layer 420, and alumina insulating layer subsequently 430, the bias material district that reserves an electrical isolation is used for constituting longitudinal biasing ferromagnetic domain 420.This initial and alumina layer 430 subsequently preferably adopts radio-frequency sputtering to form, and makes each edge that covers electrical lead 102 and MTJ 100 fully to be 100-500A at these local thickness.This technology can cause one to have the very insulator of high integrality, because guarantee that it is very important that sense current can bypass pass hard longitudinal biasing district 420.Hard bias layer 420 is preferably the CoPtCr alloy, preferably adopts directional deposition, and for example ion beam sputter deposition constitutes, and does not so just have imbricate, and the thickness of deposit is about the twice of the thickness of sensing layer 132.In a stripping technology, photoresist layer 410 and aluminium oxide and hard bias layer on it are removed then, obtain the longitudinal biasing district 420 of the electrical isolation of a left side that is positioned at MTJ 100 and right side edge.Figure 11 C shows the net result of this technology, for the sake of clarity shows the isolation edge of insulator.Next step shown in Figure 11 D, adopts an other lithography step, utilizes photoresist layer 440 to limit an open region 445, and the deposit ferromagnetic material is to constitute the back to horizontal bias area 425 therein.This lithography step also defines the backward dege edge of mtj sensor 100.Carry out the left side in a series of similar above-mentioned formation hard bias district 420 and those ion etchings of right side edge, deposit alumina insulating layer 460 and hard ferromagnetic material and step such as peel off form the back to zone 425, and structure afterwards is shown in Figure 11 E.Next step adopts photolithography by photoresist layer 470 (Figure 11 F) being carried out the initial cut height (before the polishing) that deposit and Butut constitute MTJ 100.At last, unnecessary tunnel junction material is removed,, finish the making of the MTJ reading magnetic head shown in Figure 11 G up to electronic conduction layer 102 by ion etching.The making of MTJ MR magnetic head structure has just been finished basically like this, only needs the last electrical lead of making device.
In order to make the MTJ device obtain symmetrical output characteristics, the direction of magnetization of ferromagnetic sensing layer 132 must remain on the direction shown in Fig. 4, does not promptly have cross stream component in a longitudinal direction.This point can realize by the various equivalent transverse magnetic field that the ferromagnetic sensing layer of balance is experienced under the situation without any the probe field that is produced by recording medium.Dominant ferromagnetic coupling field H between sensing and fixed ferromagnetic layer so just F, the demagnetization field H that fixed ferromagnetic layer produces DAnd keep a kind of balance between the lateral offset field by continuum boundary biasing layer 320 or transverse bias layer 420 generations.Pointed in the MTJ device as the front, because tunnel current is mobile along the normal of each layer of structure, therefore when electric current flowed in film, the field of inducting was very little.H FDepend on the character at the interface between ferromagnetic thin film and the actual knot and the thickness of knot fatefully.H FVariation can be from several oersteds (Oe) to 20-50Oe.H DDepend on the geometry of sensor, the promptly final swath height SH and the thickness t of fixed ferromagnetic layer, and fixing ferromagnetic magnetization M, variation relation is [4 π * (t/SH) * M].Therefore, for t=50 , t=50 , SH=10,000 , M=800emu/cm 2Situation, Ho is in the 40Oe scope.Can change H by the geometry of change sensor and the characteristic at interface DAnd H FFor example adopt the overlapping structure of being introduced in the IBM United States Patent (USP) of quoting previously 5,465,185 of antiparallel fixed bed can make H DMinimum.The Net magnetic moment of this layer equates that with the difference between two fixed films this difference is about 5 , so H DDrop to about 4Oe.H FCan change by the character that changes the interface.
The lead-in wire 104 Bututs well after, MTJ MR magnetic head structure is finished basically, also needs the magnetic moment of fixed ferromagnetic layer 118 is collimated to suitable direction.Be used for and Fe-Mn layer 116 that fixed ferromagnetic layer 118 carries out exchange coupling is antiferromagnetic when deposit.But its magnetic moment must collimate again and make it with fixed ferromagnetic layer 118 exchange couplings to take place on suitable orientation.Structure is placed in the annealing furnace, temperature is brought up to about 180 ℃, this temperature is than the branch deblocking temperature height of Fe-Mn.Under this temperature, no longer produce exchange anisotropy between Fe-Mn and the fixed ferromagnetic layer 118.In magnetic field, two-layer 116,118 coolings can be produced the exchange anisotropy of ferromagnetic layer 118.The orientation of the magnetic moment of fixed ferromagnetic layer 118 is along the direction of externally-applied magnetic field.Like this, the magnetic field that applies in annealing furnace can be fixed on the magnetic moment of fixed ferromagnetic layer 118 on the desired direction perpendicular to ABS, shown in the arrow among Fig. 4 119.This result's generation is owing under the situation that ferromagnetic layer 118 is arranged the Fe-Mn layer is cooled off, and adopts externally-applied magnetic field to magnetize along the direction that requires.Therefore, be lower than under the piecemeal of Fe-Mn (blocking) temperature, though there is the externally-applied magnetic field that is produced by recording medium, the magnetic moment of fixed ferromagnetic layer 118 does not rotate basically.
The final swath height SH of MTJ 100 in the device is forward sense edge polishing to a final yardstick that forms by with photoetching, gets back to line 161 (Fig. 6), makes, and has so just finished the structure shown in Fig. 8 and 9.
Magnetism bias iron layer 320 and 420,425 can be made by the high coercivity material of an individual layer, and this material can be the alloy of Co and one or more other elements, for example Co-Pt bianry alloy, or Co-Pt-Cr ternary alloy three-partalloy (for example, Co 75Pt 12Cr 13) or Co-Pt-Ni ternary alloy three-partalloy or Co-Cr-Ta ternary alloy three-partalloy.Except adopting individual layer high coercivity material, the magnetism bias iron layer can be that wherein the antiferromagnet film and first ferromagnetic thin film contact and interface exchange coupling takes place by one first ferromagnetic thin film and the double-layer film structure that antiferromagnet film constitutes.Antiferromagnet film guarantees the direction of the magnetic moment of first ferromagnetic thin film along expectation.Ferromagnetic thin film can be Ni-Fe and antiferromagnet film can be Ni-Mn.In this bilayer film embodiment, antiferromagnet film must adopt a kind of its minute deblocking temperature and the branch deblocking temperature of the material that adopted of inverse ferric magnetosphere 116 material of enough difference is arranged.The branch deblocking temperature of Ni-Mn is higher than 450 ℃, and the branch deblocking temperature of Fe-Mn is about 200 ℃.Therefore by the exchange bias field that inverse ferric magnetosphere provided with higher minute deblocking temperature, can be by at first device heats being fixed along cooling off in the magnetic field of the direction of any one ferromagnetic layer (150 or 118) orientation to the temperature that is higher than this piecemeal value and at one, ferromagnetic layer and have between the inverse ferric magnetosphere of higher minute deblocking temperature exchange coupling takes place.Then, in second step, when being cooled to the high slightly temperature of branch deblocking temperature than another inverse ferric magnetosphere, the orientation (the perhaps orientation of device) in magnetic field revolved turning 90 degrees then further cooling.
Provided the detailed introduction that the MTJ device is used as the MR reading magnetic head above.But the present invention is applicable to that fully other uses the occasion of MR sensor, for example is used for measuring element, such as the sensor of the rotation of wheel of the bus or gear, or is used for measuring the sensor of linear position.
Although the present invention illustrates especially and introduced with reference to preferred embodiment, those professional and technical personnel know in the change that can carry out under the prerequisite that does not depart from the spirit and scope of the invention on various forms and the details.Therefore, only as the usefulness of explanation, its scope is defined by appended claim in the invention of announcement.

Claims (20)

1. magnetic tunnel device that links to each other with sensing circuit is used for changes in resistance in the sensitive detection parts, and this device comprises:
A substrate;
First conductive lead wire that is made on the substrate;
A magnetic tunnel-junction lamination that is made on first conductive lead wire, comprise one at the fixed ferromagnetic layer that does not have to have under the situation of externally-applied magnetic field fixed magnetic moment, one and the contacted insulating tunnel barrier layer of fixed ferromagnetic layer, and one and the contacted sensing ferromagnetic layer of insulating tunnel barrier layer, sensing ferromagnetic layer is a rectangle, and a long backward dege edge lateral edge relative with two, that lack some is arranged;
One and contacted second conductive lead wire of magnetic tunnel-junction lamination;
One be made on the substrate, round the above-mentioned back of sensing ferromagnetic layer to lateral edge and with this back to the separated magnetism bias iron layer of lateral edge, the magnetic moment of magnetism bias iron layer is used for not having under the situation of externally-applied magnetic field the magnetic moment with sensing ferromagnetic layer be biased in a preferred direction, magnetism bias iron floor wherein comprise two near two lateral edge that lay respectively at sensing ferromagnetic layer lateral section and above-mentioned backward dege edge that is positioned at sensing ferromagnetic layer near back to the district, wherein the orientation of the magnetic moment of lateral section is different to the orientation of the magnetic moment of distinguishing with the back;
One with magnetism bias iron layer and sensing ferromagnetic layer in the above-mentioned back of sensing ferromagnetic layer to the lateral edge place separately, discontiguous electrical insulator layer each other, insulation course wherein also with two lateral section and back to distinguishing;
In view of the above, when conductive lead wire with after sensing circuit links to each other, vertical current is crossed the resistance of electric current of each layer of above-mentioned lamination by the relative orientation decision of the magnetic moment of fixing and sensing ferromagnetic layer, and sense current can avoid bypass to enter above-mentioned magnetism bias iron layer.
2. according to the device of claim 1, wherein the magnetic moment of magnetism bias iron layer is in the plane of this layer, it is oriented in greater than-90 degree less than between+90 degree, wherein 0 degree is consistent with the longitudinal direction that is parallel to for the backward dege edge of the sensing ferromagnetic layer of rectangle, and along in the magnetic moment direction that does not have sensing layer under the situation of externally-applied magnetic field.
3. according to the device of claim 1, the orientation of the magnetic moment of wherein fixing and sensing ferromagnetic layer is orthogonal not having under the situation of externally-applied magnetic field.
4. according to the device of claim 1, wherein insulation course is also with magnetism bias iron layer and at least one above-mentioned conductive lead wire electrical isolation.
5. according to the device of claim 1, wherein first conductive lead wire is a bottom lead, and the magnetic tunnel-junction lamination is made in and makes on the substrate that the fixed ferromagnetic layer and first conductive lead wire are conductings, and second conductive lead wire is a top lead, electrically contacts with sensing ferromagnetic layer.
6. according to the device of claim 1, wherein first conductive lead wire is a bottom lead, and the magnetic tunnel-junction lamination is made in and makes on the substrate that the sensing ferromagnetic layer and first conductive lead wire are conductings, and second conductive lead wire is a top lead, electrically contacts with fixed ferromagnetic layer.
7. according to the device of claim 1, wherein all of above-mentioned lamination layer all adopt same, have an extrorse rectangle of sides adjacent.
8. according to the device of claim 1, wherein the magnetic tunnel-junction lamination also comprise one with the contacted inverse ferric magnetosphere of fixed ferromagnetic layer, be used for the magnetic moment of fixed ferromagnetic layer being fixed on preferred direction by interface exchange coupling.
9. according to the device of claim 1, wherein the magnetism bias iron layer is by comprising Co, and the alloy of Pt and Cr is made.
10. according to the device of claim 1, wherein the magnetism bias iron layer comprises a ferromagnetic thin film and an antiferromagnet film that contacts and carry out interface exchange coupling with above-mentioned ferromagnetic thin film.
11. according to the device of claim 10, wherein ferromagnetic thin film is made of the alloy of a kind of Ni and Fe, and antiferromagnet film wherein is made of the alloy of a kind of Ni and Mn.
12. a magnetic tunnel-junction magnetic resistance reading magnetic head that is used for surveying the data that are recorded on the magnetic medium, magnetic head has the sensing surface of facing with medium, comprising:
A substrate;
A fixed ferromagnetic layer that is made on the substrate, the direction of magnetization of fixed ferromagnetic layer are regularly along the direction vertical with sensing surface, and making is having under the externally-applied magnetic field situation that comes from medium, and direction of magnetization is not rotated;
An insulating tunnel barrier layer that is positioned on the fixed ferromagnetic layer and is in contact with it;
A sensing ferromagnetic layer that is positioned on the tunnel barrier layer and is in contact with it, its magnetization orientation is along the preferred orientations parallel with sensing surface, and the direction of magnetization of the fixed ferromagnetic layer when not having externally-applied magnetic field is vertical, and come from existence under the situation of externally-applied magnetic field of medium, direction of magnetization can rotate freely, and sensing ferromagnetic layer is a rectangle, and its long sensing edge is parallel with sensing surface, its long backward dege edge is parallel with sensing edge, and two weak points some, relative lateral edge;
One be made on the substrate, round the above-mentioned back of sensing ferromagnetic layer to lateral edge and with this back to the separated magnetism bias iron layer of lateral edge, be used for not having under the situation of externally-applied magnetic field direction of magnetization be biased in above-mentioned preferred direction with sensing ferromagnetic layer, magnetism bias iron floor wherein comprise two near two lateral edge that lay respectively at sensing ferromagnetic layer lateral section and above-mentioned backward dege edge that is positioned at sensing ferromagnetic layer near back to the district, wherein the orientation of the magnetic moment of lateral section is different to the orientation of the magnetic moment of distinguishing with the back;
One between biasing and sensing ferromagnetic layer, be used for a electric insulation layer with biasing layer and sensing layer insulation, insulation course wherein also with two lateral section and back to distinguishing;
The pair of conductive lead-in wire, each conductive lead wire links to each other with one of sensing layer with fixed bed respectively, and by insulation course and biasing layer electrical isolation, in view of the above, when sense current was flowed through between two conductive lead wires, current vertical was passed the insulating tunnel barrier layer and is not entered the biasing layer.
13. according to the magnetic head of claim 12, also comprise one and the contacted inverse ferric magnetosphere of fixed ferromagnetic layer, it fixes the direction of magnetization of fixed ferromagnetic layer by interface exchange coupling.
14. magnetic head according to claim 12, wherein first of conductive lead wire is made on the substrate, and inverse ferric magnetosphere wherein is made on the substrate, between substrate and fixed ferromagnetic layer, fixed ferromagnetic layer is made on the inverse ferric magnetosphere and with it and contacts, in view of the above, the direction of magnetization of fixed ferromagnetic layer can fix by the interface exchange coupling with inverse ferric magnetosphere.
15. according to the magnetic head of claim 12, wherein first of conductive lead wire is made on the substrate, and sensing layer wherein is between first conductive lead wire and insulating tunnel barrier layer.
16. magnetic head according to claim 12, fixed ferromagnetic layer wherein, tunnel barrier layer and sensing ferromagnetic layer are made a lamination, the edge of fixed ferromagnetic layer and tunnel barrier layer and the rectangular edges of sensing ferromagnetic layer are coplanes, and insulation course wherein is with above-mentioned lamination and magnetism bias iron layer and the insulation of above-mentioned conductive lead wire.
17. magnetic head according to claim 12, wherein the direction of magnetization of magnetism bias iron layer is in the plane of this layer, it is oriented in greater than-90 degree with less than between+90 degree, wherein, 0 degree is consistent with the longitudinal direction that is parallel to for the backward dege edge of the sensing ferromagnetic layer of rectangle, and along in the direction of magnetization that does not have sensing layer under the situation of externally-applied magnetic field.
18. according to the magnetic head of claim 12, magnetism bias iron layer wherein is by comprising Co, the alloy of Pt and Cr is made.
19. according to the magnetic head of claim 12, wherein the magnetism bias iron layer comprises a ferromagnetic thin film and an antiferromagnet film that contacts and carry out interface exchange coupling with above-mentioned ferromagnetic thin film.
20. according to the magnetic head of claim 19, wherein ferromagnetic thin film is made of the alloy of a kind of Ni and Fe, and antiferromagnet film wherein is made of the alloy of a kind of Ni and Mn.
CN99106498A 1998-05-29 1999-05-14 Magnetic tunnel junction magnetoresistive read head with longitudinal and transverse bias Expired - Fee Related CN1113334C (en)

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US6005753A (en) 1999-12-21
KR100304024B1 (en) 2001-09-26
CN1237755A (en) 1999-12-08
JPH11353621A (en) 1999-12-24
MY116029A (en) 2003-10-31
SG82614A1 (en) 2001-08-21
KR19990088455A (en) 1999-12-27

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